Another Polish official has called out Germany over WWII reparations, claiming that up to $850 billion (€690 billion) are owed after 6 million Polish citizens were killed during the nearly six-year occupation.

“We are talking about very large, but justified amounts of compensation for war crimes, for destroyed cities, villages and the lost demographic potential of our country,” said Polish politician Arkadiusz Mularczyk of the Law and Justice party (PiS) in an interview with Polsat News.

Over the last year, Polish politicians have made repeated calls for reparations from Germany as deep cracks have formed between Poland and the EU. Eight years after the fall of the Nazi regime, Poland decided to forego further reparations from Germany in a 1953 agreement. Polish authorities have claimed it's invalid because it was directed by Moscow when Poland was a satellite of the Soviet Union.

Last year, a research group within Poland’s lower house of parliament, the Sejm, began reviewing whether this would be possible according to TheLocal. The results are expected this year - which Mularczyk suspects could be in the $850 billion range.

In August, the head of the Polish PiS party, Jaroslaw Kaczynski, accused Germany of "rejecting" its WWII responsibilities - and said reparations should be on the table. "We are talking about huge sums and also the fact that the Germans have for years rejected their responsibility for the Second World War," Kaczynski told Catholic radio station Radio Maryja.

Execution of ethnic Poles by German SS Einsatzkommando soldiers in Leszno, October 1939

Kaczynski's brother and former President Lech Kaczynski - who died in 2010 - had estimated when he was mayor of Warsaw that the had cost the capital city alone $45.3 billion.

Last September, Poland's foreign minister demanded "serious talks" with Germany over the issue.

Poland’s foreign minister Witold Waszczykowski told local radio station RMF that “serious talks” were needed with Germany to "find a way to deal with the fact that German-Polish relations are overshadowed by the German aggression of 1939 and unresolved post-war issues."

He said Poland’s material losses were about $1 trillion, or higher.

Polish defense minister Antoni Macierewicz also accused European critics of trying to “erase” the fate of the Poles at German hands during the war “from the historical memory of Europe”.

The country’s right-wing government has dismissed a 1953 resolution by Poland’s former communist government which dropped any claim to reparations from Germany, and are instead claiming that Germany is “shirking” its moral responsibility.

Relations between Berlin and Warsaw have been off late over issues including Germany’s push to share responsibility for refugees across Europe - which Poland has rejected - to the European Commission’s infringement procedure against PiS plans to have more control over the judiciary. Last August the EU sued Poland, Hungary and the Czech Republic, forcing them to accept refugees even as the rest of Europe turns a blind eye to the 100 thousand refugees that have made landfall in recent months in Italy.

Poland has not made an official demand to date, while Germany has repeatedly said there is no legal basis for reparations due to the 1953 agreement. There have, however, been individual to Poles who were forced laborers or victims of Nazi medical experiments during the wartime occupation.